Which of the following database access models is supported by JDBC and can
provide reliable control over data source access?

A.
two-tier

B.
three-tier

C.
four-tier

D.
five-tier

Explanation:
Quoted directly from Sun’s Java document site at
http//developer.java.sun.com/ In the three-tier model, commands are sent to a
“middle tier” of services, which then sends the commands to the data source. The
data source processes the commands and sends the results back to the middle tier,
which then sends them to the user. MIS directors find the three-tier model very
attractive because the middle tier makes it possible to maintain control over access
and the kinds of updates that can be made to corporate data. Another advantage is
that it simplifies the deployment of applications. Finally, in many cases, the
three-tier architecture can provide performance advantages.